package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;
    @Resource
    private IBlogService blogService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }
    @Override
    public Result queryBlogById(Long id) {
        // 查询博客
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("笔记不存在");
        }
        // 查询博客对应的用户
        queryBlogUser(blog);
        // 查询博客是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        //1.获取登录用户
        UserDTO userDTO = UserHolder.getUser();
        if (userDTO == null){
            //用户未登录,无需查询是否点赞
            return;
        }
        Long userId = UserHolder.getUser().getId();
        //2.判断是否点过赞
        String key = BLOG_LIKED_KEY + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        //2.判断是否点过赞
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.未点赞,点赞数+1
        if (score == null){
            boolean success = update().setSql("liked = liked + 1").eq("id", id).update();
            //判断数据库更改是否成功
            if (success){
                //成功则写入redis
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }
        else {
            //4.已点赞,点赞数—1并从set集合中移除。
            boolean success = update().setSql("liked = liked - 1").eq("id", id).update();
            //判断数据库更改是否成功
            if (success){
                //成功则写入redis
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }

        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        //1.查询top5的点赞用户
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        //3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id",ids).last("ORDER BY FIELD(id, " + idStr +")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        //4.返回
        return Result.ok(userDTOS);
    }

    @Override
    public Result savaBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean success = save(blog);
        if (!success){
            return Result.fail("新增笔记失败!");
        }
        //查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //获取粉丝id
        for (Follow follow : follows) {
            //获取粉丝的id
            Long userId = follow.getUserId();
            //为每个粉丝创建一个收件箱
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.查询收件箱
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> tuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if (tuples == null || tuples.isEmpty()){
            return Result.ok();
        }
        List<Long> ids = new ArrayList<>(tuples.size());
        long minTime = 0;
        int os = 1;
        //3.解析数据：blogId、minTime、offset
        for (ZSetOperations.TypedTuple<String> tuple : tuples) {
            //获取id
            String blogId = tuple.getValue();
            ids.add(Long.valueOf(blogId));
            //获取分数(时间戳)
            long time = tuple.getScore().longValue();
            if (time == minTime){
                os++;
            }
            else {
                minTime = time;
                os = 1;
            }
        }
        //4.解析id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = blogService.query()
                .in("id",ids).last("ORDER BY FIELD(id, " + idStr +")").list();
        for (Blog blog : blogs) {
            // 查询博客对应的用户
            queryBlogUser(blog);
            // 查询博客是否被点赞
            isBlogLiked(blog);
        }
        //5.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);
        return Result.ok(r);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
